Designed for competition 351 Windsor Ford V8's from 1969 and later with the following heads Edelbrock Performer RPM heads 60259, Victor Jr. heads 77169, Victor heads 77219 or similar heads. Two versions available 2980 fits SVO blocks with a 9.2 deck height and 2981 fits standard 351W blocks with a 9.5 deck height. Ideal for both oval track and drag racing engines operating between 3500 and 7500 rpm. Runners have a 2.70 square - inch cross sectional area. Carburetor Recommendations Any size or type of carburetor class allows. Installation Notes Recommended intake gasket Edelbrock 7220 or Fel - Pro 1262. Manifold height 2980 A - 5.59, B - 5.59 2981 A - 5.75, B - 5.75.